O-RADS Calculator (US and MRI)

Choose the lexicon descriptor that fits the lesion and fill in the details it needs – size, colour score, papillary projections, menopausal status on ultrasound; fluid type, wall enhancement and solid-tissue enhancement curve on MRI. The category, the ACR imaging recommendation and the clinical referral update as you type.

Disclaimer:

Implements the ACR O-RADS US v2022 assessment categories and classic benign lesion table (November 2022) and the ACR O-RADS MRI risk stratification system. Provided "as is" without warranty of any kind, express or implied, including accuracy, completeness or fitness for a particular purpose. For educational purposes only. The user is solely responsible for verifying results against the source guideline and for all clinical decisions.

O-RADS US v2022

ScoreRiskDescriptorsImaging management
1 Normal ovaryNo lesion; follicle ≤ 3 cm or corpus luteum (premenopausal)None
2 Almost certainly benign< 1 %Simple cyst < 10 cm; unilocular smooth non-simple cyst or bilocular smooth cyst < 10 cm; typical hemorrhagic cyst, dermoid or endometrioma < 10 cm; paraovarian cyst, peritoneal inclusion cyst, hydrosalpinx (any size)Simple cyst: none if ≤ 5 cm premenopausal or ≤ 3 cm postmenopausal, otherwise ultrasound in 12 months. Non-simple / bilocular: none if ≤ 3 cm premenopausal, 12 months if ≤ 3 cm postmenopausal, 6 months if 3–10 cm. Hemorrhagic cyst: none ≤ 5 cm premenopausal, 2–3 months if larger or early postmenopausal. Dermoid and endometrioma: 12 months if not excised (postmenopausal endometrioma: confirm at 2–3 months first)
3 Low risk1 to < 10 %Classic benign ovarian lesion ≥ 10 cm; uni- or bilocular smooth cyst ≥ 10 cm; unilocular cyst with irregular wall; multilocular smooth cyst < 10 cm with CS < 4; smooth solid lesion with CS 1, or with shadowing and CS 2–3Consider ultrasound within 6 months if not excised; US specialist or MRI for solid lesions
4 Intermediate risk10 to < 50 %Bilocular cyst with irregular walls; multilocular smooth cyst ≥ 10 cm or CS 4, or irregular any size; unilocular cyst with solid component and < 4 papillary projections; bi-/multilocular cyst with solid component and CS 1–2; smooth non-shadowing solid lesion with CS 2–3US specialist, or MRI with O-RADS MRI score, or per gyn-oncologist protocol
5 High risk≥ 50 %Unilocular cyst with ≥ 4 papillary projections; bi-/multilocular cyst with solid component and CS 3–4; smooth solid lesion with CS 4; irregular solid lesion; ascites and/or peritoneal nodulesPer gyn-oncologist protocol
  • Colour score (CS): 1 none, 2 minimal, 3 moderate, 4 very strong intralesional flow. A solid component protrudes ≥ 3 mm into the lumen; a papillary projection is one surrounded by fluid on three sides. Blood products and dermoid contents are not solid. Shadowing must be diffuse or broad.
  • Postmenopausal = ≥ 1 year of amenorrhoea (early < 5 years, late ≥ 5 years); if uncertain or the uterus is absent use age > 50 (early 50–54, late ≥ 55). A typical hemorrhagic cyst should not occur in late postmenopause and is re-scored with other descriptors.
  • Follow-up of O-RADS 2 lesions: if smaller (≥ 10–15 % decrease), stop; if stable, ultrasound at 24 months from the initial exam; if enlarging, ultrasound at 12 and 24 months then gynaecology.

O-RADS MRI

ScorePPVDescriptors
1 Normal ovariesNo lesion; follicle, hemorrhagic cyst or corpus luteum ≤ 3 cm in a premenopausal patient
2 Almost certainly benign< 0.5 %Unilocular cyst, any fluid, no wall enhancement; unilocular cyst with simple or endometriotic fluid and a smooth enhancing wall; lesion with lipid and no enhancing solid tissue (a minimally enhancing Rokitansky nodule is allowed); solid tissue homogeneously dark on T2 and DWI; dilated tube with simple fluid and thin smooth wall; paraovarian cyst with thin smooth wall
3 Low risk≈ 5 %Unilocular cyst with proteinaceous, hemorrhagic or mucinous fluid and a smooth enhancing wall; multilocular cyst without lipid or solid tissue; solid tissue with a low-risk time-intensity curve; dilated tube with non-simple fluid and thin wall, or simple fluid and thick smooth wall
4 Intermediate risk≈ 50 %Solid tissue with an intermediate-risk curve, or enhancing ≤ outer myometrium at 30–40 s without DCE; lipid-containing lesion with a large volume of enhancing solid tissue
5 High risk≈ 90 %Solid tissue with a high-risk curve, or enhancing > outer myometrium at 30–40 s without DCE; peritoneal, mesenteric or omental nodularity or irregular thickening with or without ascites
  • Solid tissue is enhancing tissue shaped as a papillary projection, mural nodule, irregular septation or wall, or a larger solid portion. Its time-intensity curve is compared with outer myometrium on DCE MRI with a time resolution ≤ 15 s; accuracy falls without DCE.
  • Positive predictive values are from the O-RADS MRI validation study (Thomassin-Naggara 2020) and include borderline tumours. Clinical management follows the ACR governing concepts: O-RADS MRI 2 needs no further imaging work-up, 3 goes to a gynaecologist, 4 and 5 to gynaecologic oncology.

References

  1. Strachowski LM, Jha P, Phillips CH, et al. O-RADS US v2022: An Update from the American College of Radiology's Ovarian-Adnexal Reporting and Data System US Committee. Radiology. 2023;308(3):e230685. doi:10.1148/radiol.230685
  2. Andreotti RF, Timmerman D, Strachowski LM, et al. O-RADS US Risk Stratification and Management System: A Consensus Guideline from the ACR Ovarian-Adnexal Reporting and Data System Committee. Radiology. 2020;294(1):168–185. doi:10.1148/radiol.2019191150
  3. Sadowski EA, Thomassin-Naggara I, Rockall A, et al. O-RADS MRI Risk Stratification System: Guide for Assessing Adnexal Lesions from the ACR O-RADS Committee. Radiology. 2022;303(1):35–47. doi:10.1148/radiol.204371
  4. Thomassin-Naggara I, Poncelet E, Jalaguier-Coudray A, et al. Ovarian-Adnexal Reporting Data System Magnetic Resonance Imaging (O-RADS MRI) Score for Risk Stratification of Sonographically Indeterminate Adnexal Masses. JAMA Netw Open. 2020;3(1):e1919896. doi:10.1001/jamanetworkopen.2019.19896
  5. American College of Radiology. O-RADS US v2022 Assessment Categories; O-RADS MRI Risk Stratification and Management System. www.acr.org/Clinical-Resources/Clinical-Tools-and-Reference/Reporting-and-Data-Systems/O-RADS